1. Field of the Invention
This invention covers a system consisting of a transmitter and multiple receivers for radio communication.
2. Description of Related Art
Apart from long distance telecommunications, this invention concerns radiocommunication at sight; i.e. radiocommunications for direct instruction or correction of people operating under the direct control of an instructor or trainer (sports training, ski, horse-riding and swimming lessons, safety on sea, group excursions, work control, police actions etc.). In the radiocommunication at sight sector, a vast product range is already available on the market which have, however, numerous drawbacks.
The first of these disadvantages lies in the fact that all hitherto known systems are transceivers, which means that trainer and trainee, or instructor and pupil are both equipped with a transceiver set with a considerable purchase and investment cost and a far from negligible weight and volume to carry along.
The second drawback is that these transceiver sets can only be carried by hand so that they cannot be easily used by sportsmen or other people who need to have their hands free. Transceivers with headsets are also known, but this solution is rather cumbersome (since it requires an earpiece, microphone and antenna) and cannot always be used. Furthermore, these known transceiver types are battery-energized and these batteries have to be periodically replaced.
Even if they are fitted with rechargeable batteries, each set needs individual recharging which causes considerable inconvenience and loss of time.
Another disadvantage concerns the high purchase costs when a considerable number of transceiver sets are needed; their storage also becomes more difficult requiring more space, while handling and use may be troublesome.